Even though Cereberus stats look really good at first, he has one big problem holding him down. His element-combination is pretty disastrous. Having an extensive weakness against Water is what is holding this guy back.

This results in other damage dealers, like Flamator or Rexathor, simply outperforming him both offensively as well as defensively. Though he may look cool and be a nice addition to your team, there are other minions simply doing his job better without having this huge weakness. Don't forget that water moves are a very common occurance, so if you pick this guy up, be prepared to randomly get OHKO'd at times.

Cerberus' size and resemblance in both name and appearance to a mythological creature (the Greek Cerberus), plus its powerful moves, suggest (hypothetically) that it may have been intended to be a Titan at some point during the development of Min Hero.